Cosmologic philosophy: Egnor on Big Bang, etc. (Introduction)

by David Turell , Sunday, August 29, 2021, 15:54 (1182 days ago) @ dhw

DAVID: In theoretical physics time runs both forwards and backwards. And we consider our universe as in spacetime.

dhw: How does that come to mean that Guth & Co have proved that time did not exist before our BB?

DAVID: that is what they claimed

dhw: That is the argument you supported when you wrote: “there is no before before the BB. Time didn’t exist. This was proven by Guth, Borde and Valenkin by mathematics years ago, presented by my books and here.”

DAVID: My only prior to the/our BB reality is God.

dhw: Which already = a before, and which leaves open the possibility that your God could have created countless BBs, and which therefore leaves open the possibility that Guth and Co. have got it wrong. (And even if one doesn't believe in God, no-one can possibly know that there was nothing before our BB.)

Or that there was something other than God.

dhw: I am not insisting on anything except the fact that nobody can possibly prove that nothing, including time, existed before our BB. But if, as you have agreed is possible, your God created a sequence of BBs before our own, then every BB would have come after its predecessor and before its successor in the sequence of before-during-after which you have accepted as a definition of time. I don't know why you keep defending an argument which you yourself keep demolishing.

DAVID: Do you really understand what I have presented? If there was a sequence of BB's they did not exist in a 'time' external to them or by being sequential create time. The only times before ours occurred within those previous BB's, not between them.

dhw: You agree that time could have existed within possible previous BBs, so you reject Guth and Co’s claim to have proven that there was no time before the BB. The only disagreement we now have is that you refuse to recognize that if time – as you agree – is the sequence of before-during-after, there is a before each BB and an after each BB, as well as a during each BB. Therefore there was time between BBs.

And my point is that any time that existed before our BB existed only in past BB's if they really happened. There is no time between theoretical BBs. Time exists only within spacetime in BBs.